8 results on '"Shortest path problem"'
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2. A Hybrid Routing Approach Using Two Searching Layers.
- Author
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Koca, Gonca Ozmen and Yetkin, Seda
- Subjects
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GRAPH algorithms , *SEARCH algorithms , *DECISION making - Abstract
This paper considers SUB_GOALs by using basic A* algorithm and Subgoal Graphs in a hybrid approach to execute optimal route. SUB_GOALs identified with pre-searching from basic A* at break points and Subgoal Graphs at corners of obstacles are added to SUB_TABLE to expedite the final searching in the hybrid approach. Map to work on is divided to subregions with decision-making process by using line-of-sight to avoid redundant searching. In the final searching layer, all feasible SUB_GOALs gained from decision-making process in the same subregion are connected to find final solutions of routes. Solutions achieved in the divided subregions are evaluated and combined to discover the final optimal route. The proposed hybrid approach is applied to three different scenarios in various dimensions of maps. In these three scenarios, the shortest route without hitting obstacles is calculated as 46.67, 57.76 and 124.7 units, respectively, and compared with other search algorithms. Simulation results of route planning are demonstrated to exhibit the effectiveness of the proposed hybrid approach. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. An approach towards decision making and shortest path problems using the concepts of interval‐valued Pythagorean fuzzy information.
- Author
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Jan, Naeem, Aslam, Muhammad, Ullah, Kifayat, Mahmood, Tahir, and Wang, Jun
- Subjects
FUZZY graphs ,DECISION making ,SUPPLY chain management ,FUZZY sets ,CONCEPTS - Abstract
A pythagorean fuzzy set is a generalized fuzzy structure that copes with imprecisions of real life accurately and with a larger domain. The aim of this manuscript is to develop the notion of graph for newly established concept of interval‐valued Pythagorean fuzzy set. We introduced the concept of interval‐valued Pythagorean fuzzy graph (IVPyFG) and discussed its related ideas with the help of examples. The significance of using interval‐valued fuzzy concepts over non‐interval‐valued fuzzy concepts are demonstrated numerically. Further, the advantages of using the new approach over the pre‐existing ideas are demonstrated with the help of numerical examples. The main goal of this article is to study three types of decision‐making problems using the framework of IVPyFGs. These three problems include the problem of selection of the best university in a network of universities, a supply chain management problem and the shortest path problem. The comparison of the new approach toward these problems with existing approaches is also established. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. A SCENARIO-BASED SHORTEST PATH ALGORITHM FOR OPTIMIZING THE SEQUENCE OF CHOICES UNDER UNCERTAINTY.
- Author
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GASPARS-WIELOCH, Helena
- Subjects
DECISION making ,INDUSTRIAL efficiency ,TECHNOLOGICAL innovations ,PLANNING ,UNCERTAINTY - Abstract
Copyright of Scientific Papers of Silesian University of Technology. Organization & Management / Zeszyty Naukowe Politechniki Slaskiej. Seria Organizacji i Zarzadzanie is the property of Silesian Technical University, Organisation & Management Faculty and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
5. On the Shortest Path Game.
- Author
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Darmann, Andreas, Pferschy, Ulrich, and Schauer, Joachim
- Subjects
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GRAPH theory , *DECISION making , *POLYNOMIAL time algorithms , *ACYCLIC model , *DYNAMIC programming - Abstract
In this work we address a game theoretic variant of the shortest path problem, in which two decision makers (players) move together along the edges of a graph from a given starting vertex to a given destination. The two players take turns in deciding in each vertex which edge to traverse next. The decider in each vertex also has to pay the cost of the chosen edge. We want to determine the path where each player minimizes its costs taking into account that also the other player acts in a selfish and rational way. Such a solution is a subgame perfect equilibrium and can be determined by backward induction in the game tree of the associated finite game in extensive form. We show that the decision problem associated with such a path is PSPACE-complete even for bipartite graphs both for the directed and the undirected version. The latter result is a surprising deviation from the complexity status of the closely related game Geography . On the other hand, we can give polynomial time algorithms for directed acyclic graphs and for cactus graphs even in the undirected case. The latter is based on a decomposition of the graph into components and their resolution by a number of fairly involved dynamic programming arrays. Finally, we give some arguments about closing the gap of the complexity status for graphs of bounded treewidth. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
6. Vervet monkey (Chlorocebus pygerythrus) behavior in a multi-destination route: Evidence for planning ahead when heuristics fail
- Author
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Julie A. Teichroeb and Eve A Smeltzer
- Subjects
0106 biological sciences ,Convex hull ,Computer science ,Physiology ,Social Sciences ,Marine and Aquatic Sciences ,lcsh:Medicine ,Monkeys ,01 natural sciences ,Travelling salesman problem ,Choice Behavior ,Cognition ,Chlorocebus aethiops ,Medicine and Health Sciences ,Psychology ,Heuristics ,Vervet monkey ,Foraging ,lcsh:Science ,Problem Solving ,Mammals ,Multidisciplinary ,biology ,Animal Behavior ,Behavior, Animal ,Heuristic ,05 social sciences ,Cognitive Heuristics ,Eukaryota ,Bees ,Insects ,Vertebrates ,Research Article ,Freshwater Environments ,Primates ,Mathematical optimization ,Arthropoda ,Movement ,Decision Making ,Bumblebees ,010603 evolutionary biology ,Animals ,0501 psychology and cognitive sciences ,050102 behavioral science & comparative psychology ,Motion planning ,Behavior ,Ecology and Environmental Sciences ,lcsh:R ,Organisms ,Cognitive Psychology ,Biology and Life Sciences ,Aquatic Environments ,Bodies of Water ,biology.organism_classification ,Animal Cognition ,Invertebrates ,Hymenoptera ,Lakes ,Shortest path problem ,Path (graph theory) ,Amniotes ,Earth Sciences ,Cognitive Science ,lcsh:Q ,Physiological Processes ,Sleep ,Zoology ,Neuroscience - Abstract
Animal paths are analogous to intractable mathematical problems like the Traveling Salesman Problem (TSP) and the shortest path problem (SPP). Both the TSP and SPP require an individual to find the shortest path through multiple targets but the TSP demands a return to the start, while the SPP does not. Vervet monkeys are very efficient in solving TSPs but this species is a multiple central place forager that does not always return to the same sleeping site and thus theoretically should be selected to find solutions to SPPs rather than TSPs. We examined path choice by wild vervets in an SPP experimental array where the shortest paths usually differed from those consistent with common heuristic strategies, the nearest-neighbor rule (NNR-go to the closest resource that has not been visited), and the convex hull (put a mental loop around sites, adding inner targets in order of distance from the edge)-an efficient strategy for TSPs but not SPPs. In addition, humans solving SPPs use an initial segment strategy (ISS-choose the straightest path at the beginning, only turning when necessary) and we looked at vervet paths consistent with this strategy. In 615 trials by single foragers, paths usually conformed to the NNR and rarely the slightly more efficient convex hull, supporting that vervets may be selected to solve SPPs. Further, like humans solving SPPs, vervets showed a tendency to use the ISS. Paths consistent with heuristics dropped off sharply, and use of the shortest path increased, when heuristics led to longer paths showing trade-offs in efficiency versus cognitive load. Two individuals out of 17, found the shortest path most often, showing inter-individual variation in path planning. Given support for the NNR and the ISS, we propose a new rule-of-thumb termed the "region heuristic" that vervets may apply in multi-destination routes.
- Published
- 2018
7. Cell transmission model of dynamic assignment for urban rail transit networks
- Author
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Guangming Xu, Feng Shi, Shuo Zhao, and Feilian Zhang
- Subjects
Urban rail transit ,Computer science ,0211 other engineering and technologies ,lcsh:Medicine ,Social Sciences ,Transportation ,02 engineering and technology ,Urban Environments ,Cognition ,Beijing ,Psychology ,Cell Cycle and Cell Division ,lcsh:Science ,Cell Transmission Model ,Queueing theory ,021103 operations research ,Multidisciplinary ,Applied Mathematics ,Simulation and Modeling ,05 social sciences ,Transportation Infrastructure ,Terrestrial Environments ,Cell Processes ,Physical Sciences ,Engineering and Technology ,Assignment problem ,Algorithms ,Network Analysis ,Research Article ,Schedule ,Mathematical optimization ,Computer and Information Sciences ,Decision Making ,Research and Analysis Methods ,Civil Engineering ,0502 economics and business ,Railroads ,050210 logistics & transportation ,lcsh:R ,Ecology and Environmental Sciences ,Urbanization ,Cognitive Psychology ,Biology and Life Sciences ,Cell Biology ,Models, Theoretical ,Computing Methods ,Roads ,Transmission (telecommunications) ,Shortest path problem ,Resource allocation ,Cognitive Science ,lcsh:Q ,Mathematics ,Neuroscience - Abstract
For urban rail transit network, the space-time flow distribution can play an important role in evaluating and optimizing the space-time resource allocation. For obtaining the space-time flow distribution without the restriction of schedules, a dynamic assignment problem is proposed based on the concept of continuous transmission. To solve the dynamic assignment problem, the cell transmission model is built for urban rail transit networks. The priority principle, queuing process, capacity constraints and congestion effects are considered in the cell transmission mechanism. Then an efficient method is designed to solve the shortest path for an urban rail network, which decreases the computing cost for solving the cell transmission model. The instantaneous dynamic user optimal state can be reached with the method of successive average. Many evaluation indexes of passenger flow can be generated, to provide effective support for the optimization of train schedules and the capacity evaluation for urban rail transit network. Finally, the model and its potential application are demonstrated via two numerical experiments using a small-scale network and the Beijing Metro network.
- Published
- 2017
8. Compromising system and user interests in shelter location and evacuation planning
- Author
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Barbaros Ç. Tansel, Hande Yaman, and Vedat Bayram
- Subjects
Engineering ,Travel time ,System-optimal ,Operations research ,Traffic control ,shelter ,Poison control ,Transportation ,Management Science and Operations Research ,Transport engineering ,Constrained System Optimal ,Constrained systems ,Second Order Cone Programming ,Point (geometry) ,Evacuation Traffic Management ,Nonlinear mixed integer programming ,Integer programming ,Civil and Structural Engineering ,Shelter locations ,Economic and social effects ,business.industry ,Traffic management ,System optimal ,Evacuation plan ,Shelter Location ,Emergency traffic control ,Traffic Assignment System Optimal ,Graph theory ,Second-order cone programming ,hazard management ,Shortest path problem ,Traffic assignment ,business ,numerical model ,Decision making ,optimization - Abstract
Cataloged from PDF version of article. Traffic management during an evacuation and the decision of where to locate the shelters are of critical importance to the performance of an evacuation plan. From the evacuation management authority’s point of view, the desirable goal is to minimize the total evacuation time by computing a system optimum (SO). However, evacuees may not be willing to take long routes enforced on them by a SO solution; but they may consent to taking routes with lengths not longer than the shortest path to the nearest shelter site by more than a tolerable factor. We develop a model that optimally locates shelters and assigns evacuees to the nearest shelter sites by assigning them to shortest paths, shortest and nearest with a given degree of tolerance, so that the total evacuation time is minimized. As the travel time on a road segment is often modeled as a nonlinear function of the flow on the segment, the resulting model is a nonlinear mixed integer programming model. We develop a solution method that can handle practical size problems using second order cone programming techniques. Using our model, we investigate the importance of the number and locations of shelter sites and the trade-off between efficiency and fairness. 2014 Elsevier Ltd. All rights reserved.
- Published
- 2015
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